17th century items

The doddering Hans effect

Another well-worn example bites the dust? You remember that famous study in which the participants, if primed with words connoting agedness, walked more slowly when leaving the lab.

A new study by the Belgian team of Stéphane Doyen, Olivier Klein, Cora-Lise Pichon, and Axel Cleeremans not only failed to replicate the effect, but also appeared to show that the effect observed in the original study was owing to the experimenters’ expectations.

Experimenters’ expectations seem to provide a favorable context to the behavioral expression of the prime. Obviously, this interpretation remains tentative, as we do not know how this process operates. However, it is likely that [experimenter-subjects] who expect their participants to walk slower behave differently than those who expect their participants to walk faster and that such behavioral cues are picked up by participants.

Key findings:

The setup was one that included not only the usual subjects being primed or not with a scrambled-sentence task, but also other “experimenter-subjects” whose task it was to time the usual subjects’ passage down the hall as they left the lab. Doyen et al “were indeed able to obtain the priming effect on walking speed for both subjective and objective timings. Crucially, however, this was only possible by manipulating [experimenter-subjects’] expectations in such a way that they would expect primed participants to walk slower”.

Subjective timings (with a stopwatch) yielded errors when experimenter-subjects were told that subjects would be primed to walk faster as well as when they were told that subjects would be primed to walk slower. But objective timings yielded an effect only when the priming was for walking more slowly; no effect was observed when the priming and the experimenter--subjects’ expectations were at odds.

The authors agree that unconscious behavioral priming appears to be well established,

in line with our result it seems that these methods need to be taken as an object of research per se before using it can be considered as an established phenomenon.

It’s worth noting that Doyen et al do not report any awareness on the subjects’ part of having been cued by the experimenter-subjects, even though there was some awareness (as revealed by a forced-choice test) of the priming (not as priming, but as a salient feature of the stimulus).